In recent years, there has been increasing attention to fuel cells as a new energy source. The fuel cells include solid oxide fuel cells (SOFC: Solid Oxide Fuel Cell), molten carbonate fuel cells, phosphoric-acid fuel cells, and solid polymer fuel cells. Among these fuel cells, for the solid oxide fuel cells, the use of liquid constituents is not always required, and internal reforming is possible in the case of using hydrocarbon fuels. For this reason, research and development on solid oxide fuel cells have been actively carried out.
For example, Patent Document 1 discloses, as an interconnector for solid oxide fuel cells, an interconnector formed from: a perovskite-type oxide represented by the general formula: Ln1-xAexMO3-δ (1) (where Ln represents at least one element selected from lanthanoids, Ae represents one or two or more elements selected from the group consisting of Sr, Ba, and Ca, M represents one or two or more elements selected from the group consisting of Ti, Zr, Al, Ga, Nb, Ta, Fe, Co, Ni, Cu, Mn, Mg, Rh, Pd, Pt, and Au, 0≦x≦1, and δ represents a value specified to meet the charge neutrality condition); and silica, in which the content percentage of the silica in the entire interconnector is 5 mass % to 14 mass %. In Patent Document 1, the interconnector has the function of electrically connecting fuel cells to each other. Patent Document 1 states that the use of the interconnector can suppress leakage of oxidant gas or fuel gas, because the interconnector described in Patent Document 1 has a dense structure.
Patent Document 1: Japanese Patent Application Laid-Open No. 2010-186645